Which of the following has the maximum number of atoms?

The ratio of moles of atoms in 12g of magnesium and 16g of sulphur will be:

If 12 gram of carbon has x atoms, then the number of atoms in 12 grams of magnesium will be:

If 1 gram of sulphur dioxide contains x molecules, how many molecules will be present in 1 gram of oxygen?

(S = 32 u; O = 16 u)

The mass of one molecule of a substance is 4.65 × 10^-23 g. What is its molecular mass? What could this substance be?